1. Field of the Invention
The present invention relates to improving the quality of display systems.
2. Background Art
Present day computers have vastly improved graphics processing capabilities compared to computers of just a few years ago. Nevertheless, increasingly stringent requirements are imposed upon modern graphics processors partly due to the complexity of the graphics being rendered and the demands of high quality displays. Increases in the speed and complexity of operations, and the desire to reduce costs can expose various issues with graphics processing platforms.
The graphics processing system in a computer system may exist either as an integrated system of the computer system, or as a separate graphics controller card that is plugged into the computer system. In the former case, graphics processing modules generally compete for system resources, such as memory, with other system components. In the latter case, the separate graphics controller card may include some of its own resources, such as a memory, a processor, graphics processing modules, and display generation modules.
In either case, it often happens during program execution that contention for resources has a negative impact on the generated output. In graphics processing, for example, the graphics processing pipeline trying to access video data in a shared memory may be delayed due to multiple devices in the computer system attempting to access the same shared memory. Such contention delays occur at least in part because the independent interfaces available to access a memory are few, and the number of modules that can concurrently attempt accessing the memory can overwhelm the available independent interfaces. Contention delays can have a substantial negative impact on the performance of a computer system. Various techniques exist to reduce contention while maintaining a satisfactory speed of system operation.
In addition to decreasing the performance efficiency of the computer system, contention delays in the graphics processing system can cause visual defects in displayed data. Defects in displayed data may affect the quality of the display presented to the user, and/or inject erroneous information to display data that is further processed before display to a user. For example, contention induced delays in accessing shared memory may cause the display of old data in some situations. For example, one or more pixels in a screen may be displayed based on old data already in display memory from a previous display frame, while the rest of the data is based on a current video frame. For many applications, such defects may be highly undesirable.
What are needed therefore are systems and methods for reducing visual defects that result from contention for system resources in graphics processing systems.